The StreamGraph shows the usage over time for the words most highly associated with the search word. One of these series together with a time period are in a selected state and coloured red. The tweets that contain this word in the given time period are shown below the graph.

You can either enter a random search word or your username. Then StreamGraph grabs the data of the 200 latest tweets containing the keyword. See the graph in this post for the visualization of our Twitter account. Check out the launch date of the iPhone to see how accurate the visualization is.